The Comparison of Erosion Rates in Grassland, Teak Forest, Crops Land, and Gliricidia Forest Plantation in Wanagama Edu Forest

Wanagama forest is an integral part of a nearby village. This forest is left unprotected, so local people can easily enter the forest area to take non-timber forest products, including cropland and grass. The increasing demand for grass for feeding the cattle in Wanagama resulted in a larger area of grassland. Therefore, it is highly important to review and measure the erosion rate of the grassland compared to other land uses. This research aims to measure the erosion rates of four land uses and determine the correlation between rainfall and erosion at those four land uses: grassland, teak forest, crops land, and Gliricidia forest plantation. In measuring the erosion rates, this research uses four plots of 22 x 4 meters established at those four land uses. Each plot has two drums at the outlet. We took the erosion samples at every single rainfall event. To investigate the rainfall, there were two ombrometers installed in the field. The results show that the grassland has the lowest erosion rate (0.45 tons/ha) compared to a teak forest (0.5 tons/ha), crops land (0.84 tons/ha), and Gliricidia plantation forest (1.66 tons/ha). The rainfall has a positive coefficient correlation to erosion; the lowest was in grassland (r = 0.723), followed by teak forest (r = 0.828), Gliricidia (r = 0.830), and Crops land (0.873). The higher the rainfall depth will result in the higher erosion rate at the four land uses.